Which Mineral is Rich in Fish? Unpacking the Nutritional Powerhouse

January 10, 2026 •

4 min read

According to the Washington State Department of Health, fish is not only an excellent source of omega-3s and protein but also rich in essential minerals like selenium, iodine, calcium, and phosphorus. This diverse mineral profile makes fish a nutritional powerhouse, contributing significantly to overall human health by supporting numerous bodily functions.

Quick Summary

Fish is a potent source of numerous minerals, including highly beneficial selenium, iodine, and phosphorus, crucial for metabolic and skeletal health. Many varieties also supply bioavailable heme iron and zinc, offering a dense nutritional package for overall wellness.

Key Points

Selenium is particularly rich in fish: Species like tuna, sardines, and shrimp are potent sources of selenium, an antioxidant that also helps counteract mercury's effects.
Marine fish provide significant iodine: Seafood, including cod, haddock, and shellfish, concentrates iodine from the sea, making it a key dietary source for thyroid function.
Phosphorus supports bone strength and energy: Fish and shellfish offer high amounts of phosphorus, a vital mineral for bone mineralization and energy metabolism.
Fish contains highly absorbable heme iron: Unlike the non-heme iron in plants, the heme iron found in fish is readily absorbed by the body, aiding in red blood cell production.
Shellfish are a top source of zinc: Oysters, crab, and lobster are exceptionally rich in zinc, a mineral crucial for immune system function and wound healing.
Fish bones are an excellent calcium source: When consuming fish with edible bones, like canned sardines and salmon, you gain a bioavailable source of calcium for skeletal health.

Fish is widely celebrated for its rich content of omega-3 fatty acids and high-quality protein, but its abundance of essential minerals is equally impressive and vital for human health. These minerals play a role in everything from maintaining bone density to regulating metabolism and supporting a healthy immune system. While it is difficult to pinpoint a single mineral as the absolute richest due to variations between species, some minerals are exceptionally concentrated in fish and shellfish and provide unique health benefits.

The Standout Mineral: Selenium

Selenium (Se) often stands out as a mineral particularly rich in fish, playing a crucial role as an antioxidant. This trace element is a component of selenoproteins, which help protect cells from damage caused by free radicals. A notable health benefit of selenium from fish is its ability to counteract the potential toxicity of mercury, another substance found in certain seafood. The molar ratio of selenium to mercury in most ocean fish is favorable, meaning the selenium content often protects against any harm from mercury exposure, rather than contributing to it.

Top Sources of Selenium

Several fish species are particularly good sources of this antioxidant mineral:

Yellowfin Tuna: A 3-ounce serving of cooked yellowfin tuna can provide over 160% of the Daily Value for selenium.
Sardines: Both fresh and canned sardines are excellent sources of selenium.
Shrimp: This popular shellfish is a reliable source, containing 76% of the Daily Value in a 3-ounce serving.
Alfonsino: Research indicates this fish has one of the highest selenium concentrations in its muscle tissue.

Iodine for Thyroid Health

Iodine is another essential mineral abundantly found in fish and is critical for the production of thyroid hormones. These hormones regulate metabolism, growth, and energy expenditure. Deficiency in iodine can lead to thyroid enlargement (goiter) and metabolic issues. Marine fish and shellfish, in particular, accumulate iodine from seawater, making them significantly richer sources than freshwater fish.

Iodine in Marine vs. Freshwater Fish

Marine species like haddock, cod, and shellfish have much higher iodine content due to their aquatic environment.
Freshwater species, such as rainbow trout or carp, have considerably lower iodine levels.

Phosphorus for Bones and Energy

Phosphorus is the second most abundant mineral in the human body, with the majority stored in bones and teeth. Fish are excellent sources of phosphorus, which works synergistically with calcium to maintain skeletal strength. Beyond bone health, phosphorus is crucial for energy metabolism, as it is a key component of adenosine triphosphate (ATP), the body's primary energy molecule.

Phosphorus Content in Fish

Fish species offer varying levels of phosphorus:

Sardines: Known for their edible bones, canned sardines are extremely high in both phosphorus and calcium.
Salmon: A fatty fish that provides both phosphorus and omega-3 fatty acids.
Cuttlefish: A mollusk with one of the richest phosphorus contents among seafood, supplying 387 mg per 100g cooked serving.

Calcium, Iron, and Zinc

While selenium, iodine, and phosphorus are particularly noteworthy, fish also provide significant amounts of other critical minerals.

Calcium: Fish bones, especially in canned fish like sardines and salmon, are a great source of highly bioavailable calcium. A study found that calcium from salmon and cod bones is well-absorbed in humans, making fish by-products a viable and sustainable calcium source.
Iron: Fish contains heme iron, which is absorbed much more efficiently by the body than the non-heme iron found in plant-based foods. Tuna, mackerel, salmon, and shellfish like clams and oysters are excellent sources of this mineral.
Zinc: Particularly abundant in shellfish, zinc is essential for immune function, wound healing, and cell division. Oysters are famously high in zinc, but crab and lobster are also excellent sources.

Mineral Content in Popular Fish: A Comparison Table

Here's a comparison of the mineral content in 3-ounce (approx. 85g) cooked servings of popular fish varieties, based on available data:


Fish/Shellfish	Selenium (mcg)	Iodine (mcg)	Phosphorus (mg)	Iron (mg)	Zinc (mg)
Yellowfin Tuna	92	10	284	1.02	~0.5
Sardines (canned)	45	60	490	1.6	1.1
Cooked Shrimp	42	~15	198	1.4	1.6
Atlantic Mackerel	40	~15	217	1.63	~0.5
Wild Salmon	~35	~15	226	0.25	~0.3
Cooked Crab	~40	~35	278	~0.5	3.2

Note: Values are approximate and can vary based on sourcing and preparation. Iodine for certain species not explicitly listed was estimated based on average marine fish content.

Wild-Caught vs. Farmed Fish: Mineral Variations

The mineral content in fish can vary depending on whether it is wild-caught or farm-raised. This difference is largely due to diet and environment.

Wild-Caught Fish: Often consume a more varied, natural diet from their marine environment, which can lead to a richer and more diverse mineral profile.
Farmed Fish: Are fed a controlled, commercial diet. While this allows for fortification of certain nutrients, it can also lead to variations compared to their wild counterparts. For example, the iodine content can differ depending on the feed and water source. Some studies also find that wild fish may have higher concentrations of certain minerals like manganese, while others, like farmed salmon, may have consistent nutrient levels due to their managed diets.

Conclusion

While fish is rich in a multitude of essential minerals, selenium and iodine are two of the most notably abundant. Selenium offers powerful antioxidant properties and protection against mercury, while iodine is vital for thyroid hormone production. Additionally, fish and especially shellfish provide excellent sources of phosphorus for bone health and energy, as well as highly absorbable heme iron and immune-supporting zinc. Incorporating a variety of fish into your diet, including both fatty and shellfish options, is the best strategy to maximize the intake of this diverse array of health-promoting minerals.

For more detailed information on the health benefits of various fish components, you can refer to the National Institutes of Health study on dietary intake and nutrient composition of seafood, available via PMC: https://www.ncbi.nlm.nih.gov/books/NBK605432/.

Frequently Asked Questions

While fish contain numerous minerals, selenium is particularly notable. It is found in high concentrations in many fish, including tuna and sardines, and provides powerful antioxidant benefits.

Yes, marine fish and shellfish typically have much higher iodine content than freshwater fish, as they absorb it directly from the seawater. Mineral levels can also vary based on the specific species and its diet.

Yes, studies have shown that the calcium found in fish bones, such as those in canned sardines and salmon, is highly bioavailable and well-absorbed by the human body.

Oily fish and shellfish are great sources of iron. Tuna, mackerel, sardines, and bivalves like clams and oysters are particularly good sources of highly absorbable heme iron.

Cooking methods like baking, grilling, and steaming generally preserve most minerals. Boiling can cause some minerals, like phosphorus and magnesium, to leach into the water, which is often discarded.

Mineral content can differ based on diet and environment. Wild-caught fish may have a more varied profile, while farmed fish have a more consistent mineral content due to controlled feeds, which can be fortified.

Selenium is also found in nuts, grains, and meat; iodine in dairy and iodized salt; phosphorus in dairy, nuts, and legumes; iron in red meat, beans, and leafy greens; and zinc in red meat, nuts, and legumes.